Academic journal article Alcohol Health & Research World

Alcohol's Effects on Male Reproduction

Academic journal article Alcohol Health & Research World

Alcohol's Effects on Male Reproduction

Article excerpt

The male reproductive system consists of the hypothalamus, the anterior pituitary gland, and the testes. Alcohol can interfere with the function of each of these components, thereby causing impotence, infertility, and reduced male secondary sexual characteristics. In the testes, alcohol can adversely affect the Leydig cells, which produce and secrete the hormone testosterone. Studies found that heavy alcohol consumption results in reduced testosterone levels in the blood. Alcohol also impairs the function of the testicular Sertoli cells that play an important role in sperm maturation. In the pituitary gland, alcohol can decrease the production, release, and/or activity of two hormones with critical reproductive functions, luteinizing hormone and follicle-stimulating hormone. Finally, alcohol can interfere with hormone production in the hypothalamus. KEY WORDS: AODE (alcohol and other drug effects); hypothalamus; pituitary gland; male genitals; reproductive function; testosterone; hormone metabolism; heavy AOD use; cell type; luteinizing hormone; follicle stimulating hormone; gonadotropin RH; secretion; animal model; male; literature review

In both men and women, the hormones regulating reproduction form a complex and finely tuned system that affects virtually every cell system in the body. The male reproductive system consists of three parts: a brain region called the hypothalamus, the anterior pituitary (a gland that is located at the base of the brain but is not considered a brain region), and the testes. This article briefly reviews how those three organs and the hormones they produce cooperate to ensure and regulate male reproductive functioning. The article then describes alcohol's effects on each of the three organs, drawing on studies in both humans and animals. The discussion also points out potential therapies for preventing or reversing alcohol's deleterious effects.

OVERVIEW OF THE MALE REPRODUCTIVE SYSTEM

Of the three components of the male reproductive system, the hypothalamus and the anterior pituitary gland have solely regulatory functions, which are mediated by the hormones secreted from these two organs. The third component, the testes, also produces key hormones controlling male sexual characteristics and behaviors, the most important of which is testosterone. In addition, the testes are responsible for sperm production.

The hypothalamus, which is located at the base of the brain, is often called the master control unit of the reproductive systems of both men and women. (For more information on the hypothalamus and the hormones it produces, see the article by Hiller-Sturmhofel and Bartke, pp. 153-164.) Among other hormones, the hypothalamus produces gonadotropinreleasing hormone (GnRH). GnRH is secreted in pulses into a system of blood vessels that connect the hypothalamus to the anterior pituitary gland, which is located just beneath the hypothalamus.

In response to the GnRH stimulus, the anterior pituitary gland produces two hormones that control reproductive functions-luteinizing hormone (LH) and follicle-stimulating hormone (FSH) -and releases them into the general circulation. Those two hormones have different functions in men and women. In men, LH stimulates the testes to produce the hormone testosterone, whereas FSH plays an important role in sperm maturation. (For information on the roles of LH and FSH in women, see the article by HillerSturmhofel and Bartke, pp.153-164.) In addition, the anterior pituitary gland produces the hormone prolactin. In men, elevated prolactin levels play a role in reproduction by indirectly suppressing testosterone levels in the body.1

The testes consist primarily of the seminiferous tubules, the site of sperm cell formation and maturation. Interspersed among those tubules are so-called interstitial cells, including a cell type called Leydig cells, which produce the "male" sex hormone testosterone.2 In addition to its function in reproduction, testosterone helps regulate many diverse body functions, including bone and muscle development; red blood cell turnover; and development and maintenance of male sexual characteristics, such as sexual drive (i. …

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